During the cold winter months, a sheet of ice covers a lake near the Arctic Circle. At the beginning of spring, the ice starts to melt.

The variable

ss

s

models the ice sheet's thickness (in meters)

tt

t

weeks after the beginning of spring.

s=-0.25t+4s=-0.25t+4

s=-0.25t+4

By how much does the ice sheet's thickness decrease every

66

6

weeks

Decreased by 1.5 meters and is now at 2.5 meters.

Step-by-step explanation:

s=-0.25t+4 represents the thickness of the ice over t weeks. To find the thickness at 6 weeks, substitute t=6.

s = - 0.25 (6) + 4 = 2.5 meters

It started at t = 0 at 4 meters. So it decreased by 1.5 meters.

The start of spring has 4 meters because when t = 0, s = - 0.25 (0) + 4 = 4